Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 14: Surface Magnetism – Skyrmions (jointly with MA, O)

TT 14.10: Talk

Monday, March 16, 2015, 12:00–12:15, EB 301

Energy-dependent magnetic contrast of a nanoscale spin helix measured by STM — •Safia Ouazi, Soo-Hyon Phark, Jeison A. Fischer, Dirk Sander, and Jürgen Kirschner — Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany

Helical spin order has been revealed for Fe bilayer islands on Cu(111) by spin-polarized scanning tunneling spectroscopy (SP-STS) in a magnetic field at 10 K [1]. We measure the magnetic contrast, as given by the difference in differential conductance for states with and without spin helix [1], as a function of the gap voltage applied between tip and sample. Thus, we obtain the first spatially- and energy-resolved map of spin contrast for a nanoscale spin spiral. The wave vector describing the helical spin order remains constant in the energy range -0.8eV to +0.5eV, whereas the spin contrast shows a strong modulation. This result identifies a novel aspect of SP-STM to characterize complex spin order with respect to the corresponding electronic band structure. We discuss the results in view of a partial energy gap associated with the non-collinear spin order.

[1] S.-H. Phark, J.A. Fischer, M. Corbetta, D. Sander, K. Nakamura, J. Kirschner, Nat. Commun. 5:5183 doi:10.1038/ncomms6183 (2014).